/in/foo.cc: In function 'int main()':
/in/foo.cc:34:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<st>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |         for(int i=0;i<nt[x].size();i++)
      |                     ~^~~~~~~~~~~~~